For the past half century, one of the surest paths to well-heeled financial security was becoming a corporate lawyer. Your class background didn't matter all that much, as long as you were smart enough to get into a top law school and could then endure the brutal hours of an associate at a corporate firm.
True, many associates didn't actually make partner at the very top firms, but just logging a few years at a place like Cravath, Swain, and Moore set you up to make partner elsewhere later on. One thing was certain: You wouldn't get suddenly fired as an associate.